Chlorogenic acids, caffeic acids, ferulic acids etc., which are contained in foods such as coffee, have been reported to show an excellent hypotensive action (JP-A 2006-204192, JP-B 4-29326, JP-A 3-127950). However, coffee beverages containing merely chlorogenic acids in large quantity are also reported to have no plainly recognizable hypotensive action and tend to increase the blood pressure to the contrary (Eur. J. Clin. Nutr., 53(11), 831 (1999)). Hydrogen peroxide derived from hydroxyhydroquinone contained in coffee beverages has been found to inhibit the hypotensive action of chlorogenic acids (JP-A 2006-204192). On one hand, coffee contains hydrogen peroxide which naturally emerges upon roasting (Eur. J. Clin. Nutr., 53(11), 831 (1999)), and a technology of removing hydrogen peroxide from coffee by adding catalase, peroxidase or antioxidant (JP-A 3-127950, JP-A 11-266842, JP-A 2003-81824) has been reported.
Coffee is a highly palatable beverage, and its influences on the health of human body have attracted attention in recent years. The present inventors have paid attention to a hypotensive action as one influence and reported that hydroxyhydroquinone contained in a coffee beverage composition is reduced such that the weight ratio of hydroxyhydroquinone/chlorogenic acids in the coffee beverage composition is reduced to 10/10000 or less at which the hypotensive action of coffee was recognized, and as a specific method, a method of treating a coffee extract with activated carbon has been adopted (WO-A 05/72533).
As methods of treating coffee beans, there are proposed methods such as a decaffeinating method of contacting raw coffee beans with an organic solvent, water or a supercritical fluid, a method of wash treatment, with water, of matter that has adhered to the surfaces of raw coffee beans, and a method of removing a stimulating substance by high-pressure steaming of raw coffee beans.